Generally, a sheet processing device performs specified post-processing on a sheet conveyed from an image forming apparatus. The sheet processing device includes a processing unit for performing the post-processing. A standby unit is provided above the processing unit. The standby unit temporarily holds a subsequent sheet while post-processing on the sheet is performed by the processing unit. When the processing unit is available, the standby unit drops the held sheet toward the processing unit.
A sheet bundle may be bound with an adhesive tape, and sheets of the sheet bundle may be incrementally shifted with respect to each other such that an end of the sheet bundle forms a step shape. In this case, an adhesion area of intermediate sheets of the sheet bundle with respect to the adhesive tape can be increased. However, it is difficult to shift the end of the sheet bundle to form the step shape, and a configuration of the device is likely to be complicated.